Acetylenes, oxidation

The direction of addition, verified by acetylene oxidation into a known acid, proves that the nitiilimine carbon atom adds to the terminal atom of the enyne system, which is inconsistent with the assumed polarization of the unsaturated compound H2C=CH—C=C—R from the vinyl group towardR. The authors explain this by a possible transfer of the reaction center in nitrilimine as a particle with a nucleophilic center on a carbon Ph—C=N" —N —Ph Ph—C =N =N—Ph (63ZOB3558). 

Essentially, the oxidation chemistry of the aliphatics higher than C2 has already been discussed since the initiation step is mainly CC bond cleavage with some CH bond cleavage. But the initiation steps for pure ethene or acetylene oxidation are somewhat different. For ethene the major initiation steps are [4, 39a]... 

Although no reported work is available on vinyl acetylene oxidation, oxidation by O would probably lead primarily to the formation of CO, H2, and acetylene (via an intermediate methyl acetylene) [37], The oxidation of vinyl acetylene, or the cyclopentadienyl radical shown earlier, requires the formation of an adduct [as shown in reaction (3.142)]. When OH forms the adduct, the reaction is so exothermic that it drives the system back to the initial reacting species. Thus, O atoms become the primary oxidizing species in the reaction steps. This factor may explain why the fuel decay and intermediate species formed in rich and lean oxidation experiments follow the same trend, although rich experiments show much slower rates [65] because the concentrations of oxygen atoms are lower. Figure 3.13 is a summary of the reaction steps that form the general mechanism of benzene and the phenyl radical oxidation based on a modified version of a model proposed by Emdee et al. [61, 66], Other models of benzene oxidation [67, 68, which are based on Ref. [61], place emphasis on different reactions. 

The cleavage of the elements of water takes place by the usual trans-elimination hydroxy- and aminopyrazolines without a hydrogen atom trans to the substituent are fairly stable.351 For the interaction of acetylene oxides with hydrazines see Perveev and Ershova.352... 

Figure 6.4 A dinuclear copper(I)-containing [2]-catenane formed via double acetylene oxidative coupling ...

Note recommended flame air-acetylene, oxidizing (lean, blue). 

Oxygenation of carbanions. The a1 transforming carbanions into alcohols [Pg.70]

Oxygenation of carbanions. The alkoxide form (i.e., (-BuOOLi) is capable of transforming carbanions into alcohols (after subsequent protonation). Of particular interest is the formation of acetylene oxides. 

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